Guide system for rams in press brakes and the like

ABSTRACT

IN A MACHINE OF THE PRESS BRAKE TYPE, PARTICULARLY ONE HAVING A PLATEN TYPE RAM, GUIDE MEANS ARE PROVIDED FOR THE RAM, WHICH WILL PERMIT OF HEAVY END FORCES AGAINST THE RAM SLIDEWAYS WITHOUT GALLING, WHILE PERMITTING HYDRAULIC LEVEL CONTROL OF THE RAM AND LIMITING PERMISSIBLE LONGITUDINAL DISPLACEMENT OF THE RAM TO WITHIN THE MATING ABILITY OF DIES IN THE MACHINE.

March 9, 1971 wfpEARsoN 3,568,498

GUIDE .S YSTEM FOR RAMS IN PRESS BRAKES AND THE LIKE Filed Jan. 24, 1569 2 Sheets-Sheet l FIG.

ATTORNEY March 9, 1971 GUIDE SYSTEM FOR RAMS IN PRESS BRAKES AND THE LIKE Filed Jan. 24, 1969 E- W. PEARSON 2 Sheets-Sheet 2 ATTORN EY United States Patent 3,568,498 GUIDE SYSTEM FOR RAMS IN PRESS BRAKES AND THE LIKE Eugene W. Pearson, Orinda, Calif., assignor to Pacific Press & Shear Corp. Filed Jan. 24, 1969, Ser. No. 793,801 Int. Cl. B21d 11/00 US. Cl. 72-456 Claims ABSTRACT OF THE DISCLOSURE In a machine of the press brake type, particularly one having a platen type ram, guide means are provided for the ram, which will permit of heavy end forces against the ram slideways without galling, while permitting of hydraulic level control of the ram and limiting permissible longitudinal displacement of the ram to within the mating ability of dies in the machine.

My invention relates to ram type machines such as press brakes and the like, and more particularly though not limited to one of the straight side type wherein a platent type ram is guided by corner columns.

Presses of this type are employed with mating dies having critical dimensions in length as well as in width, and consequently, to assure accurate mating of the dies and complete meshing of the same, the ram must of necessity be limited in its permissible longitudinal displacements, as well as in permissive tilting thereof from a prevailing attitude.

Where the guiding system is wholly mechanical, the permissible longitudinal displacement of the ram is determined by the spacing required to assure adequate lubrication of the slideways, and the machine housing is constructed rugged enough to restrain any tendency of the ram to shift or tilt, particularly in response to off center loads. Under such conditions, a severe unbalance of loading on the ram could cause a tilting movement of such magnitude as to cause severe galling of the slideways, and such problem is aggravated when the machine is hydraulically powered and the hydraulic motors are supported inboard of the ram slideways.

Among the objects of the present invention are (1) To provide a novel and improved ram type machine;

(2) To provide a ram machine having novel and improved guide means for the ram;

(3) To provide a platen type ram machine having guide means adapted to withstand heavy horizontal loading against the ram slideways without galling the slideways, yet permitting level control of the ram hydraulically; and

(4) To provide a platen type ram machine having novel and improved guide means which will permit hydraulic control of such ram as to attitude while limiting longitudinal displacement of the ram to within the mating ability of dies in such machine.

Additional objects of my invention will be brought out in the following description of a preferred embodiment of the same, taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a front view in elevation of a machine embodying the present invention;

FIG. 2 is a plan view looking down on the machine of FIG. 1;

FIG. 3 is vertical view partly in section through the machine of FIG. 1;

FIG. 4 is an enlarged view of a ram guide means assembly employed in the machine of FIG. 1

FIG. 5 is a view corresponding to that of FIG. 4 but depicting a modified form of guide means assembly.

Referring to the drawings for details of my invention in its preferred form, the invention is disclosed as embodied in a press brake of the type having a platen type ram 1 slidably supported between corner columns 3, 5, 7 and 9, and driven by hydraulic motors 11, 13 symmetrically mounted above the ram and each drive connected thereto by a pivotal drive coupling 15, such as disclosed, for example, in the patent to Pearson et al. No. 3,145,602 of Aug. 25, 1964, or in the patent to Eugene W. Pearson, No. 3,163,105 of Dec. 29, 1964.

Each column supports two slideways 17 and 19 for guiding such ram and limiting displacements thereof both longitudinally (left to right) as well as transversely (front to back), respectively.

Below the ram and included as a component part of the machine, is a table 21, this table being adapted to support one component of a mating die assembly (not illustrated) while the other component is mounted on the ram in alignment therewith. Upon causing the two die components to come together in mating relationship, sheet material disposed therebetween will be correspondingly deformed. To assure proper mating of the dies, necessitates placing heavy restritcions as to permissive longitudinal displacements of the ram, as well as angular rotational movements thereof.

In operation, the amount of tilt of the ram may be quite small, and, as a maximum, might be of the order of one-eighth inch. For conventional guiding, guide clearances are normally of the order of .003 inch. Thus with a three foot long guide pad, a .001 inch per foot tilt can be tolerated without binding. Anything beyond this, of course, could cause the slide pad to bear against a slideway, on more or less a line or point contact, with resulting possibility of galling the slideway.

All of which emphasizes the necessity for exercising stringent control over deviations of the ram, which not only might produce galling of the slideways when employing conventional guidance means, but which might also cause mismating of the components of a mating due assembly.

In accordance with the present invention, I provide a guide means assembly 23 between the ram and each proximate slideway, which assembly performs the multiple functions of guiding the ram in its vertical movements without galling, while permitting limited angular rotation of the ram; and precluding longitudinal displacements beyond the mating ability of any mating dies in the machine.

For details of each guide means assembly, as depicted in the enlarged view of FIG. 4, it provides for a slide pad 25 in sliding engagement with the proximate slideway, against which it is retained by resilient means interposed between the slide pad and the ram, such resilient means, in the embodiment under consideration, involving a bracket 27 on the face of the ram, opposite the slide pad, both the bracket and slide pad being recessed at corresponding vertically spaced locations to anchor a pair of heavy springs 29, 31 installed under compression.

Between the bracket and the slide pad, a pivotal relationship is established to permit, in the absence of other measures, angular or rotational displacements of the ram, it being noted that the springs 29, 31 allow for this.

To realize such pivotal relationship, in the embodiment as illustrated in FIG. 4, a spherical recess 35 is provided in the exposed side of the slide pad, to receive the spherical side 37 of a spherical segment 39 formed with a lip 41 at its lower end, extending in the direction of the bracket. The spherical segment has a planar base surface 43 at an angle to the lip, to provide an angular space between the base surface and the bracket, for reception of 3 an adjusting wedge 45. For adjusting purposes, the wedge is provided With an anchored bolt 47 at its narrow end, adapted to pass through an aligned opening in the lip, and with nuts 49, 51 mounted on such bolt to either side of the lip, the wedge may be adjusted and locked in any desired position.

In making such adjustment, limited spacing is allowed between the spherical recess and the spherical segment, such spacing determining maximum permissible longitudinal displacement of the ram, such maximum being within the mating ability of the mating dies installed in the press, and may be determined through the use of a feeler gauge inserted between the two spherical surfaces. Thus while the slide pad is resiliently maintained in its sliding relationship to the slideway, with no possibility of galling the slideway, the pivotal relationship between the pad and the ram, enables the ram to angularly rotate through a slight angle independently of the slide pad. Thus such ability to angularly rotate, which, in practice, may be stimulated by an otf center load on the ram, will enable the springs to perform their function of maintaining the slide pad in surface to surface contact with the proximate slideway. Thus the columns or machine frame as the case may be, is relieved to a great degree of resisting such turning moments as may be applied to the ram by an off center load, and consequently need not be constructed as rugged as would otherwise be the case in a conventional guide system, where ruggedness is relied on in limiting undesired displacements of the ram.

In accordance with the present invention, such permissive angular rotation of the ram is deliberately built into the guide means assemblies, for it then not only relieves the slide pad and frame of the function of resisting such angular displacements, but permits of the use of known hydraulic means for taking over this function.

A hydraulic system which is admirably adapted for this purpose is one disclosed in either the patent to Richardson No. 2,906,096 of Sept. 29, 1957 for Precision Controlled System for Press Brakes or the Like, or that disclosed in the patent to Castle No. 3,026,755 of Mar. 27, 1962 for Hydraulically Actuated Clamp for Work Severing Device, or that disclosed in the patent to Pearson et al. No. 3,143,924 of Aug. 11, 1964, for Control Means for Series Connected Cylinder Drive Assemblies. Each of such systems is a hydraulic levelling system for precluding angular deviations of a ram from a level condition.

Such a system has been modified in the patent to Pearson No. 3,152,503 of Oct. 13, 1964, for Control Means for Hold-Down Means in a Shear or Like Machine, whereby a ram may be deliberately adjusted to an outof-level position, and thereafter hydraulically retained against deviations from such attitude.

Basic to all of such systems, is a control tape 51 anchored at one end to the frame of the machine and passing over a sheave 53 at one end of the ram, then extending across the ram and under a sheave 55 at the other end of the ram, the tape, thereafter extending up to a switch box 57, housing a pair of microswitches, which control the feed of hydraulic fluid to the drive motors, in accordance with the teachings of the aforementioned patents, to compensate and correct for any undesired angular deviations of the ram. Such hydraulic control systems being prior art, may be deemed to be symbolically represented by the tape and switch box, without necessarily including all of the electrical and hydraulic circuitry depicted in the aforementioned patents.

A modified form of guide means assembly has been illustrated in FIG. to which attention will now be directed.

This embodiment is of somewhat simpler construction in that it employs a spherical segment 61 of symmetrical form which is slidably mounted in the bracket 63 which for this purpose, is substantially thicker than the bracket in the embodiment of FIG. 4. Such mounting involves providing the spherical segment with a center bolt 65 and a pair of guide pins 67, 69, each adapted to slidably fit a passageway through the bracket, the bolt extending completely through the bracket to receive a tightening nut 71. In this embodiment, adjustments are made by applying shims 73 between the spherical segment and the bracket.

Whatever guide means is employed, it is to be preferred that the pivot means of the guide means assembly and the pivot means of the proximate pivot drive coupling should have the same radius point.

From the foregoing description of my invention in its preferred form, it will be apparent that the objects of my invention have been fulfilled by the disclosure and while I have illustrated and described same in considerable detail, it will be apparent that the same is subject to alteration and modification without departing from the underlying principles involved, and I accordingly do not desire to be limited in my protection to the specific details illustrated and described except as may be necessitated by the appended claims.

I claim:

1. A machine of the press brake type having a ram movable between slideways, and hydraulic drive means pivotally connected to said ram, guide means between said ram and each of said slideways, each of said guide means including a slide pad adapted to slidably engage a slideway, means between said ram and said pad for resiliently retaining said pad in sliding engagement with said slideway, and pivotal means between said ram and said pad to permit angular movement of said ram without disturbing the sliding engagement between said pad and its associated slideway.

2. A machine in accordance with claim 1 characterized by means for maintaining said ram at a prevailing attitude.

3. A machine in accordance with claim 1 characterized by said pivotal means including pivotally cooperating components and means for adjusting clearance between said components.

4. A machine in accordance with claim 3 characterized by said pivotal cooperating components including said pad having a spherical recess in its exposed side, and a spherical segment in meshing relationship with said spherical recess.

5. A machine in accordance with claim 1 characterized by said ram being of the platen type movable between column supported slideways, a bracket on the front side of said platen type ram adjacent each end thereof, with each said guide means being located between one of said brackets and the proximate slideway, and said resilient retaining means including a pair of springs, each installed between an end of said bracket and an end of said slide pad, with said pivotal means located between said springs.

References Cited UNITED STATES PATENTS 829,682 8/1906 Taylor 72 -456 1,382,571 6/1921 Tel'hune 72456 1,566,603 12/1925 Huber 72456 2,453,875 11/1948 Terhune 72456 2,441,275 5/1948 Keagle 72456 2,906,096 9/ 1959 Richardson 6097 FOREIGN PATENTS 1,236,985 6/1960 France.

CHARLES W. LANHAM, Primary Examiner G. P. CROSBY, Assistant Examiner US. Cl. X.R. -214, 258 v 

